Weir has played three matches for Scotland but all of these caps have come from the bench. Saturday will be the first time he has started for the national side with interim boss Scott Johnson rewarding the 21-year-old for his impressive showing from the bench in Scotland's 12-8 win over Ireland in round three of the championship.

With Ruaridh Jackson relegated to the bench, Weir is hopeful that he can repay the faith that Johnson has shown in him. "I'm grateful for the opportunity to play and hopefully I can do 'Johnno' justice on Saturday," Weir said. "It will be a hugely proud moment, not only for me but for my family and friends. I'll get to share a great achievement with them and the Scottish nation as well.

"When I came on against Ireland I just wanted to bring a real energy, put a wee bit of pressure on Ireland and get a bit of territory. Our defence for the majority of the game had been outstanding, so I knew our defence could bring us points. I also wanted to try and get the guys going in attack, so I felt I did all right there."

Johnson has made an immediate impact since taking over from Andy Robinson. The squad that trudged off with the wooden spoon last year has now picked up two wins from and Weir believes it is Johnson's attention to detail, especially with the half-backs, which has played a large part in that fact.

"Johnno drills the stand-offs pretty hard," Weir said. "He wants us to know our goals, our movement onto the ball and our leadership of the team. He also wants us to know the correct calls and also to listen for our outside players and what they can see before relaying that back to everyone else and making sure we exploit the chances we get.

"We were disappointing against England but we played some great rugby against Italy. We didn't have much good ball to attack against Ireland but our defence was superb and that was what won us the game. We can still iron out the creases and hopefully against Wales people will see a rounded-off performance."